By Dr. Harry G. Preuss M.D.
The general citing of serious, ubiquitous health-involved epidemics such as obesity and diabetes is indeed widespread and has generally been recognized for many years. In contrast another very important one has been unfortunately overlooked over the same time frame. The preceding referral is to non-alcoholic fatty liver disease (NAFLD) which, even though it does have a close, maybe even dependent, relationship with the other two above-mentioned medical disturbances, is only now receiving the recognition necessary to develop strategies to overcome its too often dire consequences.
In my initial training, it was generally a routine to perform some training at a Veterans Administration Hospital (VA). There, one learns a great deal about the scourge of alcoholic liver disease and its associated disturbing elements. I must confess that in those early days I was not aware of this oncoming perturbation arising from excess fat accumulation in the liver. As mentioned above, not much emphasis was place on this particular hepatic blight then. Suffice it to say, this disorder has only recently received the widespread attention it rightly deserves from clinicians and researchers and has been said to be, if not the major reason, at least a very important factor behind an increasing number of liver transplants.
Numerous aspects of the specific pathogenesis of NAFLD are inexact, however, insulin resistance (IR) and central fat accumulation, often associated with poor life style choices in diet/exercise, appear to be crucial components in the background . Specifically, visceral fat buildup favors ensuing localization of this component to the liver [1,2]. In addition to greater liver fat buildup due to the closeness to the central fat deposits, the related IR secondary to this phenomenon appears to influence pathways of uptake, synthesis, degradation, and secretion of free fatty acids ultimately favoring even more augmented accumulation of triglycerides in the liver cells creating a malicious unhealthful cycle [1,2].
An intensified fresh awareness of this entity is no doubt due to a number of factors: first, quite recently, as implied above, it has been generally noted that this form of liver disturbance is increasing by leaps and bounds – now estimated to involve anywhere from 15-33% of the worldwide population [1-3]; second, the consciousness that it is not necessarily the non-threatening disorder as originally advertized generally [1,2]; and finally, its strong relationship to the common recognized ubiquitous entities: insulin resistance (IR), type 2 diabetes mellitus (T2DM), and the metabolic syndrome (MS} [1,3]. It is now coming to fruition that NAFLD participates strongly in the development and intensity of the other mentioned common metabolic disorders. Ironically, they, in turn, can worsen the NAFLD. Therefore, a solid understanding of the need for early recognition of NAFLD has become paramount, because this entity has created a major health crisis and prevention in early stages is preferred over long, drawn out treatment. . Also important, the major form of prevention and therapy depends on a lot of lifestyle changes in diet that results in a lessening of IR.
The first identifiable stage of NAFLD is hepatic steatosis, i.e., fat content exceeds 5% of liver volume . When first described, hepatic steatosis was generally considered to be harmless as inferred above –- simply a collection of triglycerides accumulating in the liver (1,3]. Indeed, it is an established fact now that many, maybe even the majority of patients with NAFLD maintain pure steatosis without inflammation and have benign clinical courses. However, it has been recognized more recently that although the numbers are relatively smaller, excessive hepatic triglyceride accumulation can bring on inflammation as well as hepatocellular injury (steatohepatitis) and even fibrosis — conditions that are often associated with transplantation.
In the next report, more emphasis will be on prevention and treatment of NAFLD .
- Carey E, Wieckowska A, Carey WD: Nonalcoholic fatty liver disease. Cleveland Clinic http//www.clevelandclinicmeded/medicalpubs/diseasemanagement/hepatology/nonalcoholic –fatty-liver-disease/
- Shyangdan D, Clar C, Ghouri N, Henderson R, Gurung T, Preiss D, Sattar N, Fraser A, Waugh N: Insulin sensitizers in the treatment of non-alcoholic fatty liver disease
- Kwon Y-M et al: Association of nonalcoholic fatty liver disease with component of MS according to BMI in Korean Adults. Am J Gastroenterol 107: 1852-1858, 2012.
- Preuss HG, Kaats GR, Mrvichin N, Swaroop A, Bagchi D, Clouatre D, Preuss JM: Examining the relationship between nonalcoholic fatty liver disease and the metabolic syndrome in nondiabetic subjects. J Am Coll Nutr 37:457-465, 2018.